A Goldman Sachs boss has apologised to neighbours after a basement excavation at his £7 million Kensington home caused cracks to appear in adjoining properties.

One woman had to be rescued after becoming trapped in her flat when a shift in the front door frame left her unable to open it. Other residents said cracks had appeared in their walls and stairways.

Emergency building teams were called in on Sunday when a pillar holding up the 160-year-old house’s portico cracked through. Ten tons of roofing was removed from the four-storey house in Palace Gardens Terrace to reduce weight on its foundations. The front of the building is now covered in scaffolding, steel joists and planks.

The house was bought 18 months ago by Christoph Stanger, a 46-year-old managing director at Goldman Sachs who heads its German and Austrian financing group.

He was granted planning permission for an underground extension in May last year despite objections from nine of the 11 locals consulted by Kensington & Chelsea council.

Louise Stael von Holstein, who has lived in a flat next door for 30 years, said: “They’ve been digging since the beginning of the year, down into the basement, and it’s caused the house to subside. The basement flat in my block has got cracks everywhere.”

A retired neighbour said: “We’ve had to call the contractors out six times in the past three weeks to open our own front door. One lady who lives in my block was stuck in her flat because she couldn’t get the door open from the inside. I had to come and barge it loose.”

Neighbour Jonathan Wearing added: “Once planning permission is granted there are only the fine words and empty promises of architects, surveyors and party wall agreements to protect neighbours.”

Mr Stanger apologised for the disruption and said he would compensate neighbours for any damage to their homes. He told the Standard that the excavation was necessary to build a playroom for his four children and a guest room. He plans to move in with his family in January.

He said: “I feel bad about the disruption and if there is any real damage it will be dealt with and they will be compensated.

“I have no interest in fighting with my neighbours. I want to live there and be a part of the community. I understand it can be disruptive when your neighbours are having building work done.”

Charles Penney, chairman of the local Cherry Trees Residents’ Association, said: “It’s a case of people putting economics before common sense. If it costs £1 million to do the work, the increase in the property’s value will in all probability be double that.”

A spokesman for the council, which has approved more than 400 basement extensions in recent years, said: “We are aware that basement extensions, many of which do not need planning permission, do cause concern for residents.”